Interfacial Rate Processes in Adhesion and Friction

Abstract

Adhesion between solid materials results from intermolecular interactions. The fracture resistance of an adhesive joint is, however, determined jointly by the mechanical deformation in the bulk material and the strength of the interfacial bond. The force needed to break an interfacial bond does not have a fixed value; it depends on the thermal state of the system and the rate at which the force is transmitted to the bond. The concomitant energy dissipation arising from the extension and the relaxation of the interfacial bonds contributes a significant resistance to fracture, which is clearly evident in elastomeric polymers. This issue of interfacial dissipation and its relationship to the length of the interfacial bridges and the rate of crack propagation are addressed with the kinetic theory of bond rupture in the tradition of the models developed by Eyring, Tobolsky, Zhurkov, Bueche, Schallamach, Kausch, and more recently, by Evans and Ritchie. Next, the method is extended to address the velocity-dependent sliding friction of elastomers against low energy solid surfaces. The theme of this article is to point out that certain aspects of adhesion, friction, and fracture may be described under a generalized framework of interfacial kinetics.

Mode-mixity-dependent adhesive contact of a sphere on a plane surface

“…Qualitatively similar results for the loading/unloading behaviour of PDMS were obtained in microtribometer experiments by Galliano et al (2003) and Vaenkatesan et al (2006). Ghatak et al (2000) noted that, . Experimental data for normal loading/unloading cycles on PDMS.…”

“…Chaudhury & Whitesides 1991;Brown 1993;Silberzan et al 1994;Deruelle et al 1995;She et al 1998;Chaudhury 1999). Ghatak et al (2000) noted that a kinetic theory of interface bond failure precludes adhesion reversibility, which has a basis in the so-called Lake-Thomas effect, where the energy required to fracture an elastomeric interface is amplified owing to the stretching and relaxation of polymer chains (Lake & Thomas 1967). Because of the variety and inherent complexity of such dissipation mechanisms, phenomenological models are often used to capture the dependence of the effective work of adhesion upon the rate of change of contact radius, which is analogous to a crack front velocity (e.g.…”

Molecular Origins of Elastomeric Friction

“…41 examined the pull-out of polymer chains from elastomeric networks and the associated friction. Ghatak et al 42 studied friction of polydimethylsiloxane (PDMS) on some low energy surfaces as a function of molecular weight of the polymer M and the sliding velocity. They noted that friction decreases with molecular weight.…”

Direct Probe of Interfacial Structure during Mechanical Contact between Two Polymer Films Using Infrared Visible Sum Frequency Generation Spectroscopy

“…Mechanical contact between two soft solids, particularly polymers, is of fundamental importance in the areas of friction, adhesion, and contact mechanics [1][2][3]. Although there have been numerous studies on measurements of adhesion and friction using macroscopic (surface force apparatus [4] and mechanical tribometers [5]) and microscopic 30 contact areas [6], there have been no direct measurements of interfacial structure during mechanical contact between two polymer surfaces.…”